1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor element, and more particularly, to a method of manufacturing a semiconductor element formed by bonding a silicon substrate and a glass substrate.
2. Description of the Related Art
At present, as a display element mounted on a display device such as a display, a reflective liquid crystal display element (LCOS), an organic light emitting element (organic electroluminescence (EL) element), and the like are actively researched and developed. When an LCOS or an organic light emitting element is manufactured, there are cases in which a step of bonding together a substrate (for example, a silicon substrate) on which elements are provided and a sealing substrate such as a glass substrate using a resin as an adhesive, that is, a sealing step, is included.
In the case of an LCOS, in the above-mentioned sealing step, not only the silicon substrate and the glass substrate are bonded together, but also a space between the silicon substrate and the glass substrate is filled with a liquid crystal material. Specifically, the silicon substrate and the glass substrate are bonded together using a resin sealing material provided at peripheral portions of each of the substrates, and a space between the two substrates and inside the resin seal material is filled with the liquid crystal material. In the case of an organic EL element, the above-mentioned sealing step is carried out for the purpose of blocking the organic EL element from outside air. Specifically, the silicon substrate (substrate) and the glass substrate (sealing substrate) are bonded together using a filling resin so as to cover at least the entire surface of a light emitting region, and the organic light emitting element is enclosed with the silicon substrate, the glass substrate, and the filling resin to protect the organic light emitting element from oxygen and moisture in the atmosphere.
By the way, when a semiconductor element is manufactured, from the viewpoint of production efficiency, a mother board on which multiple semiconductor elements are arranged is used. When such a mother board is used to manufacture a semiconductor element, the semiconductor element is manufactured specifically through the following steps (a) to (c): (a) a step of manufacturing multiple semiconductor elements on the mother board; (b) a step of bonding together and integrating the mother board and a glass substrate (sealing substrate) having substantially the same the size as the mother board using a resin, thereby sealing all the semiconductor elements provided on the mother board; and (c) a step of separating the semiconductor elements one by one by cutting the mother board and the glass substrate.
By the way, as a method of dividing a structure formed by bonding together a silicon substrate as a mother board and a glass substrate as a sealing substrate using a resin, for example, there is known collective cutting of the silicon substrate, the glass substrate, and the resin by dicing.
In this case, when the silicon substrate, the glass substrate, and the resin are simultaneously cut by dicing, clogging occurs because a dicing blade used strikes the resin. This clogging conspicuously reduces the dicing quality (in particular, increases chippings). Therefore, in order to maintain the dicing quality at a certain level, it is necessary to increase the replacement frequency of the dicing blade. Further, generally, the thickness of a dicing blade which can cut both silicon and glass is larger than the thickness of a dicing blade used only for silicon. Therefore, a region on the silicon substrate which is necessary for cutting the silicon substrate (cutting street) becomes larger, which results in the reduced number of semiconductor elements taken from one mother board.
Further, when dicing is carried out at a portion in which there is no resin between the silicon substrate and the glass substrate, a problem may arise that cutting water used in the dicing enters together with particles to contaminate the elements provided on the silicon substrate with the particles.
As a method of solving the above-mentioned problem which arises when a substrate is cut, Japanese Patent Application Laid-Open No. 2008-164980 proposes a method in which, when the silicon substrate and the glass substrate are cut at a portion having the resin therebetween, the cutting method is changed. Specifically, there is proposed a method in which, while the glass substrate and the resin are completely cut by dicing, the silicon substrate is half-cut by dicing.
However, even the method proposed in Japanese Patent Application Laid-Open No. 2008-164980 still cuts the resin itself by dicing, and, similarly to the case of the conventional art, the above-mentioned reduction of the dicing quality is inevitable. Further, in order to completely cut the glass substrate and the resin by dicing, it is necessary to dice to some extent an interface of the silicon substrate with the resin, and the above-mentioned dicing blade which can cut both silicon and glass is required to be used. Further, when a part of the cut portion does not include the resin therein, cutting water enters the portion which does not include the resin therein.